U.S. patent number 6,740,607 [Application Number 09/956,640] was granted by the patent office on 2004-05-25 for substrate with stretch and heat sealing properties to make a multidirectional restraint module design.
This patent grant is currently assigned to Bradford Industries, Inc.. Invention is credited to Richard J. Satin, Manuel J. Veiga.
United States Patent |
6,740,607 |
Veiga , et al. |
May 25, 2004 |
Substrate with stretch and heat sealing properties to make a
multidirectional restraint module design
Abstract
The invention is directed to coating a plurality of polyurethane
films onto a stretchable knit fabric substrate and heat sealing
such substrates together to yield an air curtain or air bag having
improved air-holding properties.
Inventors: |
Veiga; Manuel J. (Tewksbury,
MA), Satin; Richard J. (Swampscott, MA) |
Assignee: |
Bradford Industries, Inc.
(Lowell, MA)
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Family
ID: |
23275736 |
Appl.
No.: |
09/956,640 |
Filed: |
September 19, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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327245 |
Jun 7, 1999 |
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Current U.S.
Class: |
442/149;
106/287.13; 106/287.14; 139/387R; 139/410; 280/729; 442/286;
442/203; 442/182; 442/169; 442/168; 442/164; 428/166; 428/101;
280/733; 442/76; 280/728.1; 139/389; 139/384R |
Current CPC
Class: |
B32B
7/12 (20130101); B32B 27/12 (20130101); B60R
21/235 (20130101); B32B 25/10 (20130101); B32B
27/04 (20130101); B32B 27/40 (20130101); D06N
3/186 (20130101); D06N 3/145 (20130101); D06N
3/183 (20130101); B32B 5/026 (20130101); Y10T
442/2139 (20150401); B60R 2021/0018 (20130101); Y10T
428/24025 (20150115); Y10T 442/2861 (20150401); Y10T
442/2902 (20150401); B32B 2605/08 (20130101); Y10T
442/3854 (20150401); B32B 2262/0276 (20130101); Y10T
442/2893 (20150401); B32B 2262/0261 (20130101); Y10T
428/24562 (20150115); B32B 2553/02 (20130101); Y10T
442/2738 (20150401); Y10T 442/3008 (20150401); D10B
2505/124 (20130101); B60R 2021/23514 (20130101); Y10T
442/3179 (20150401) |
Current International
Class: |
B32B
27/04 (20060101); B32B 27/12 (20060101); B32B
27/40 (20060101); B60R 21/16 (20060101); D06N
3/00 (20060101); D06N 3/18 (20060101); D06N
3/12 (20060101); D06N 3/14 (20060101); B60R
21/00 (20060101); B32B 027/02 () |
Field of
Search: |
;3/383
;139/384R,389,387R,410 ;106/287.13-287.1 ;280/728.1,729,733,748.1
;442/76,164,168,169,182,203,286,149 ;428/34.1-36.9,101,166 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Publication of Clark-Schwebel Joint Ventures, C-S Integlas A.G.,
title page, Clark-Schwebel description page, contents, disclaimer
page. .
Parameters for Woven Fabric Selection (2 pages)..
|
Primary Examiner: Singh; Arti R.
Attorney, Agent or Firm: Holland Law Firm, P.L.C.
Parent Case Text
This application is a continuation of application Ser. No.
09/327,245, filed Jun. 7, 1999, now abandoned, the disclosure of
which is incorporated by reference herein and made a part of this
application.
Claims
What is claimed is:
1. A coated textile substrate for an air-holding vehicle restraint
system, which comprises: a) a textile substrate of a stretchable
knit fabric having opposed surfaces; b) a first coating layer of an
adhesive polyurethane on a surface of said textile substrate; and
c) a second coating layer of an elastomeric polyurethane on said
first coating layer.
2. The coated textile substrate of claim 1 wherein said textile
substrate is a fabric constructed from synthetic fibers.
3. The coated textile substrate of claim 2 wherein the synthetic
fibers are selected from the group consisting of polyamides and
polyesters.
4. The coated textile substrate of claim 1 wherein the adhesive
polyurethane layer is selected from the group consisting of
aliphatic or aromatic polyester or polyether polyurethanes.
5. The coated textile substrate of claim 1 wherein the adhesive
polyurethane layer is a film having a thickness of from about 0.5
mils to about 2.5 mils.
6. The coated textile substrate of claim 5 wherein the thickness of
the adhesive polyurethane film is about 1.5 mils.
7. The coated textile substrate of claim 1 wherein the elastomeric
polyurethane layer is an aliphatic or aromatic polyether or
polyester polyurethane having from about 30% to about 100% solids,
by weight.
8. The coated textile substrate of claim 1 wherein the elastomeric
polyurethane layer is a film having a thickness of from about 0.5
mils to about 8.0 mils.
9. The coated textile substrate of claim 8 wherein the elastomeric
polyurethane film has a thickness of about 2 mils.
10. The coated textile substrate of claim 1 wherein the other
surface is coated with an adhesive polyurethane forming a first
coating layer and a second coating layer of an elastomeric
polyurethane on said first coating layer.
11. The coated textile substrate of claim 1 wherein the other
surface of said knitted textile substrate is coated with a
polysiloxane.
12. An air-holding vehicle restraint system, comprising: a pair of
heat-sealed polyurethane coated knitted textile substrates; the
outer surface of each substrate having an adhesive polyurethane
film and an overlying elastomeric polyurethane film.
13. The restraint system of claim 12 wherein the heat sealed
substrates form an air-tight connection.
14. The restraint system of claim 12 wherein the knitted textile
substrates are heat-sealed about their peripheries.
15. The restraint system of claim 12 wherein the textile substrates
are sealed by radio frequency sealing, hot air sealing or
ultrasonic sealing.
16. The restraint system of claim 15 wherein the substrates are
sealed by radio frequency sealing at from about 10 to about 80
megahertz.
17. The restraint system of claim 12 wherein the air-holding
restraint system is an air bag.
18. The restraint system of claim 12 wherein the air-holding
restraint system is an air curtain.
19. The restraint system of claim 12 wherein the knitted textile
substrates are selected from the group consisting of polyesters,
polyamides or other synthetic fibers.
20. The restraint system of claim 12 wherein the adhesive
polyurethane coating layer is selected from the group consisting of
aliphatic or aromatic polyester or polyether polyurethanes.
21. The restraint system of claim 12 wherein the adhesive
polyurethane film has a thickness of from about 0.5 mils to about
2.5 mils.
22. The restraint system of claim 21 wherein the film thickness is
about 1.5 mils.
23. The restraint system of claim 12 wherein the elastomeric
polyurethane film is an aliphatic or aromatic polyether or
polyester polyurethane having a solids content of from about 30% to
about 100%, by weight.
24. The restraint system of claim 12 wherein the elastomeric
polyurethane film has a thickness of from about 0.5 mils to about
8.0 mils.
25. The restraint system of claim 24 wherein the elastomeric
polyurethane film has a thickness of about 2.0 mils.
26. An air-holding vehicle restraint system, comprising: a
polyurethane coated knitted textile substrate heat-sealed to a
polyurethane coated woven textile substrate; the outer surface of
each substrate having an adhesive polyurethane film and an
overlying elastomeric polyurethane film.
27. The restraint system of claim 26 wherein the heat sealed
substrates form an air-tight connection.
28. The air-holding vehicle restraint system of claim 26 wherein
the textile substrates are heat-sealed about their peripheries.
29. The restraint system of claim 26 wherein the textile substrates
are sealed by radio frequency sealing, hot air sealing or
ultrasonic sealing.
30. The restraint system of claim 29 wherein the substrates are
sealed by radio frequency sealing at from about 10 to about 80
megahertz.
31. The restraint system of claim 26 wherein the air-holding
restraint system is an air bag.
32. The restraint system of claim 26 wherein the air-holding
restraint system is an air curtain.
33. The restraint system of claim 26 wherein the knitted textile
substrate is selected from the group consisting of polyesters,
polyamides or other synthetic fibers.
34. The restraint system of claim 26 wherein the woven textile
substrate is nylon.
35. The restraint system of claim 26 wherein the adhesive
polyurethane coating layer is selected from the group consisting of
aliphatic or aromatic polyester or polyether polyurethanes.
36. The restraint system of claim 26 wherein the adhesive
polyurethane film has a thickness of from about 0.5 mil to about
2.5 mils.
37. The restraint system of claim 36 wherein the film thickness is
about 1.5 mils.
38. The restraint system of claim 26 wherein the overlying
elastomeric polyurethane film is an aliphatic or aromatic polyether
or polyester polyurethane having a solids content of from about 30%
to about 100%, by weight.
39. The restraint system of claim 38 wherein the overlying
elastomeric polyurethane film has a thickness of from about 0.5
mils to about 8.0 mils.
40. The restraint system of claim 39 wherein the elastomeric
polyurethane film has a thickness of about 2.0 mils.
Description
FIELD OF THE INVENTION
This invention relates to a coated knit textile fabric for use in
an air-holding vehicle occupant restraint system and, more
particularly, to a fabric having a plurality of polymeric layers
coated thereon for use in such a vehicle occupant restraint system,
the method of coating said textile knit fabric, and the air-holding
vehicle occupant restraint system formed from such coated
fabric.
BACKGROUND OF THE INVENTION
The current restraint systems for vehicles include driver side air
bags which are housed in the steering wheel in a collapsed, folded
condition adapted to be deployed instantaneously in an inflated
condition by injection of a gas upon the occurrence of a collision.
The advent of such driver-side air bags has resulted in a
significant decrease in auto fatalities.
Air bag restraint systems have also been located in the dashboard
in order to provide a comparable measure of protection to the
passenger seated adjacent the driver.
The automotive industry has recently introduced air bags which are
housed in the backs of the front seats or in the rear seats to
protect the cabin occupants in the event of a collision occurring
on either side of the vehicle.
A still further safety feature which is being marketed for
passenger vehicles, especially sport utility vehicles (SUV), are
air-holding curtains designed to provide a cushioning effect in the
event of roll-over accidents. These curtains are housed in the roof
of the vehicle and deploy along the interior sidewalls of the SUV's
cabin in the event of a rollover.
One means of improving the efficacy of air-holding vehicle
restraint systems has addressed the coatings to be applied to the
textile substrate to improve air retention.
In the prior art, coated air bags were made by coating a nylon
substrate with chloroprene or silicone. They were not, however,
susceptible to heat sealing. In order to ameliorate the problems
inherent in chloroprene and silicone rubber coatings, it has been
disclosed in the art, for example, Menzel, U.S. Pat. No. 5,110,666,
to coat knitted and woven nylon and polyester substrates with
polyurethane to provide the desired permeability to better retain
the inflation gas.
The use of a polyurethane coated fabric for use in garments and
bags is disclosed in Tschirch et al., U.S. Pat. No. 4,284,682 which
is assigned to NASA. This patent discloses a process for forming a
polyurethane elastomeric film on woven or knitted fabrics made from
cotton, rayon, polyester, polyamide, etc. and laminating with
pressure and heat. This patent discloses laminating a single layer
of polyurethane film on a fabric in order to assure that garments
or bags made therefrom would be leakproof.
Despite the advances in air bag coating technology, the problems of
controlling air permeability, air pressure, and volume still
remain. Another problem resulting in air loss stems from the fact
that during the manufacture of the air bags, they are stitched shut
by means of sewing. Inherently, each stitch creates a potential
leak which adversely affects the integrity and, hence, the air
holding capability of the bag, especially when instantaneous
deployment of an operative airbag is required.
With the advent of SUV's, the provision of adequate protection to
passengers in the event of multiple rollovers has become of prime
importance. One means of obtaining such protection is by providing
air curtains which are disposed in a collapsed condition in the
header of the SUV and which deploy in the event the vehicle rolls
over. The air-holding capability of such air curtains is critical
since they must remain inflated for an extended period of time.
Unlike air bags which are designed to inflate instantaneously, and
also deflate almost instantaneously in order to avoid injury to the
driver or the passenger from the bag itself, air curtains used in
an SUV, or in a passenger vehicle, must be capable of remaining
inflated in the range of about three (3) to about twelve (12)
seconds, depending upon the size of the curtain used and the type
of vehicle employed. The maximum inflation period should be
sufficient to protect the cabin occupants during three (3)
rollovers, which are the maximum number of rollovers which are
usually experienced.
SUMMARY OF THE INVENTION
It has now been found that by coating a plurality of polyurethane
layers onto a stretchable fabric substrate, followed by
heat-sealing two of such coated substrates together, yields an
air-holding restraint system which has superior air-holding
characteristics, viz., permeability, as well as volume and pressure
retention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a textile substrate having a
plurality of polyurethane coating layers on one surface in
accordance with the present invention.
FIG. 2 is a cross-sectional view which depicts a textile substrate
having a plurality of polyurethane coating layers on one surface in
accordance with the embodiment of FIG. 1 and a polysiloxane coating
on the opposite or reverse surface.
FIG. 3 is a cross-sectional view which depicts a textile substrate
leaving a plurality of polyurethane coating layers on one surface
in accordance with the embodiment of FIG. 1 and a polyurethane
coating on the opposite or reverse surface.
In describing the figures, similar parts in the various embodiments
will be referred to by the same numerals.
DETAILED DESCRIPTION OF THE INVENTION
It has been found that when a surface of a textile substrate having
opposed surfaces is initially coated with an adhesive polyurethane
layer and, thereafter, with an elastomeric polyurethane layer, the
coated substrate when converted into an air-holding restraint
system by joining two (2) such coated substrates together by heat
sealing, yields a restraint system having improved air
retention.
Either a polyamide or a polyester can be employed as the textile
fabric substrate, provided it is a knit fabric having
multidirectional stretch characteristics. By using a knit fabric as
the textile substrate, it will provide the occupants with the
desired pillowing or cushioning effect during a rollover. Since
woven materials lack stretchability, they would not confer the same
degree of protection.
Exemplary of the knitting methods which can be employed to make the
knit fabrics are circular knitting, raschel knitting, interlock
knitting, etc. Circular knitting is preferred since the wales and
courses are uniform, and the stretchability is uniform in all
directions. Any type of denier size can be employed to advantage.
The shape or configuration to be employed in the air holding
restraint system will depend upon its ultimate location in the
vehicle. For example, driver or passenger air bags will generally
be elliptical, spherical or circular, while air curtains will
generally be rectangular in configuration.
The coating of the knitted fabric substrate with layers of
polyurethane can be achieved by various coating methods, such as,
for example, laminating and cast coating. While cast coating will
be discussed herein in an exemplary manner, it is to be understood
that the method of the present invention for coating polyurethane
film to a stretchable knit substrate is not limited thereto.
In cast coating, as opposed to conventional coating, the coating is
applied to a release liner or paper, i.e., a paper substrate
typically coated with a releasable silicone. The release paper
provides a means similar to a conveyor belt, for example, for
coating polymers on the surface of the release paper without drying
out the polymers. When the coating operation is completed, the
release paper can be stripped off and one is left with the
composite structure which has been built up.
An elastomeric polyurethane layer is coated onto a silicone release
paper. The elastomeric layer is from about 30% to about 100% solids
by weight of an aromatic or aliphatic polyether or polyester
polyurethane, with an aromatic polyether polyurethane being
preferred. Optionally, depending on the chemical and physical
properties sought to be introduced into the air curtain or air bag
which is ultimately made from the coated fabric, there is added to
the elastomer, for example, flame-proofing agents such as aluminum
trihydrate or antimony trioxide, mildew prevention agents, such as
BP5.RTM. by Morton Thiokol, and UV and ozone resistance agents,
such as TINUVUN 765.RTM. by Ciba Geigy.
The thickness of the elastomeric polyurethane film is within the
range of about 0.5 mils to about 8.0 mils, with about 2 mil being
preferred. The elastomeric polyurethane film on the release paper
is then dried by passing it into an oven at an elevated temperature
of from about 350.degree. F. to about 450.degree. F.
Thereafter, an adhesive polyurethane layer is laid down atop the
elastomeric polyurethane layer. The polyurethane used in the
adhesive coat can be selected from among aliphatic and aromatic
polyether polyurethanes and aliphatic and aromatic polyester
polyurethanes, preferably those having a solids content of from
about 30% to about 60%, by weight. The thickness of the adhesive
polyurethane film is from about 0.5 mils to about 2.5 mils, with
about 1.5 mils being preferred.
Thereafter, continuing the cast coating process, the adhesive
polyurethane layer which has not been dried and which is still in
the wet condition, has applied thereto a
multidirectionally-stretchable knitted textile substrate.
The composite structure of polyurethane coated knit textile fabric
is then dried by passing it into an oven maintained at about
225.degree. F. to about 425.degree. F. for about 1.5 minutes to
about 3.0 minutes. The composite is advanced at a speed of about
1,000 yds per hour to about 3,000 yards per hour, with about 1,200
yds. per hour being preferred.
Thereafter, upon exiting from the oven, the silicone release paper
is stripped off leaving the polyurethane knit composite structure
depicted in FIG. 1. Embodiments of composite structures of the
present invention are set forth hereinafter with reference to the
drawing figures.
In one embodiment of the present invention, as can be seen by
reference to FIG. 1, a composite structure, generally denoted by
the numeral 10, includes a knitted fabric substrate 12, depicted
with its upper or top surface 14 coated with a film 16 of an
adhesive polyurethane, which is referred to as the prime or
adhesive coat. This serves to adhesively bond the filaments of the
textile substrate so they do not comb or unravel.
Preferably, the adhesive or prime coat layer 16 completely covers
the entire surface 14 of the knit fabric 12. Alternatively, it can
be applied as a partial coating designed to coincide with a
particular area of the fabric. Also, particular patterns, such as
stripes, wavy lines, etc., with different coating weights can be
employed to obtain the level of air permeability desired.
Referring still to FIG. 1, a second layer of an elastomeric
polyurethane film 18 is depicted. The elastomeric film layer 18 is
about 30% to about 100% solids, by weight, of an aliphatic or
aromatic polyether or polyester polyurethane.
The composite structure depicted in FIG. 1, will, in accordance
with the present invention, typically form a single panel of an air
bag or an air curtain after die cutting into the desired
configuration by the air bag manufacturer. A complementary
composite structure, similar in all respects to the structure of
FIG. 1, forms the opposite panel of the airbag or air curtain. In
accordance with the present invention, the two (2) panels are
sealed together about their peripheries by sealing the polyurethane
layers together by radio frequency (RF) sealing, hot air sealing or
ultrasonic sealing at from about 10 to about 80 megahertz and at
about 250.degree. F. to about 450.degree. F., with radio frequency
sealing being preferred. Sealing in this manner serves to insure
improved control of the air permeability of the curtain or bag,
while maintaining its integrity against air leakage, since the
problems realized by conventional closing, such as stitching or
sewing with their attendant air inherent leakage problems, are
avoided. Employing a polyurethane-radio frequency sealing system is
especially important in the manufacture of air-filled tubular
curtains since air must be held in the tubular structures
comprising the curtain for longer periods of time than with a
conventional airbag. Such curtains must open within 2 to 3
milliseconds and must stay inflated for from about 3 to about 12
seconds after deployment in the event of multiple rollovers, say,
three (3) such rollovers in a single incident.
In another embodiment of the present invention, as depicted in FIG.
2, the outer surface 14 of knit fabric 12 is coated with the same
polyurethane film layers depicted in FIG. 1. However, in this
embodiment, inner surface 20 of the knitted textile substrate is
also coated with an adhesive polyurethane film 16 and an
elastomeric polyurethane film layer 18.
In another embodiment of the present invention, as depicted in FIG.
3, surface 14 of knit fabric 12 is coated with the same
polyurethane film layers as depicted in FIG. 1. However, in this
embodiment, the bottom or inner surface 20 of fabric substrate 12
has a layer of a polysiloxane 22 coated thereto. It is then dried
in an oven at elevated temperature, say, about 250.degree. F. to
about 450.degree. F. and vulcanizes with the textile substrate. The
polysiloxane is preferably a silicone rubber elastomer. The coating
weight of the polysiloxane layer 22 on surface 20 is from about 0.5
ounces per square yard to about 5.0 ounces per square yard, with
1.2 ounces per square yard preferred. The silicone coating provides
added protection to the fabric to protect against the high
temperatures encountered during inflation with hot gases.
When the manufacturer converts two of the polyurethane coated knit
substrates into an impermeable air curtain or air bag by
radio-frequency sealing, each of the panels employed can be made
according to FIGS. 1, 2, or 3, or combinations thereof, depending
upon the ultimate characteristics to be designed into the end
product, i.e., air curtain or air bag.
In another embodiment of the present invention, which is especially
advantageous in the manufacture of air curtains, it is desirable to
employ a stretchable multidirectional knit fabric in the air bag
panel which will ultimately deploy within the passenger cabin to
provide a cushioning effect to the occupants. Sealed to that panel,
by radio frequency sealing in accordance with the present
invention, would be a polyurethane coated woven polyamide or
polyester fabric panel, for example a ballistic nylon, which would
deploy adjacent the side windows, and which would be puncture
resistant to broken glass, sharp projectiles, rocks and the like to
offer added protection to the passengers. Thus, the air curtain
would comprise a composite structure wherein a polyurethane coated
stretchable knit fabric would be heat sealed to a polyurethane
coated to a woven polyamide or polyester to provide cushioning on
the knit surface and toughness and durability on the nylon
surface.
* * * * *